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Overview

My goal is to make a Flutter ios app with AWS. I am facing an issue when adding a persistent settings model to users, who will each have a corresponding settings model from their chosen items, like in any normal app.

More specifically, I want to have a single settings entry called randomPhotoOffset, which is boolean. I was advised to use Amplify and DynamoDB to store user settings because it is scalable and offers more choices, compared to just using Cognito.

My workspace and versioning

1. Using Amplify Gen 1 and CLI
2. amplify_flutter: ^2.6.0
3. amplify_auth_cognito: ^2.5.0
4. amplify_api: ^2.6.0
5. amplify_datastore: ^2.6.0
6. Flutter sdk: ^3.5.4 I have updated my `pubspec.yaml' and my packages are all up to date and no versioning conflict occurs

Also testing on Simulator with device iPhone 16 Pro Mac on M4 Pro

The only issue

The only issue I am facing is an error I get when I toggle a button that changes one of my settings.

Exception updating user settings: ApiOperationException { "message": "No modelProvider found", "recoverySuggestion": "Pass in a modelProvider instance while instantiating APIPlugin" }

My code

main.dart This function is called after WidgetsFlutterBinding.ensureInitialized(); and before runApp().

Future<void> configureAmplify() async {
  try {
    final authPlugin = AmplifyAuthCognito();
    final apiPlugin = AmplifyAPI();
    final dataStorePlugin =
        AmplifyDataStore(modelProvider: ModelProvider.instance);

    Amplify.addPlugins(
      [authPlugin, dataStorePlugin, apiPlugin],
    );
    await Amplify.configure(amplifyConfig);

    // Start DataStore to register the model provider for GraphQL operations.
    await Amplify.DataStore.start();
  } on Exception catch (e) {
    Log.e("Error configuring Amplify: $e");
  }
}

settings.dart This is the only relevant function that is called once a button is pressed. Changes occur immediately after toggling, so a save button is avoided

Future<void> _toggleRandomPhotoOffset(bool newValue) async {
    setState(() {
      _randomPhotoOffset = newValue;
    });
    try {
      // Retrieve the current user's ID from Amplify Auth.
      final authUser = await Amplify.Auth.getCurrentUser();
      await updateUserSettings(
        userId: authUser.userId,
        randomPhotoOffset: newValue,
      );
    } catch (e) {
      Log.e("Error retrieving user or updating settings: $e");
    }
  }

settings_service.dart Here, updateUserSettings is defined

Future<void> updateUserSettings({
  required String userId,
  required bool randomPhotoOffset,
}) async {
  // Create a new UserSettings object.
  final settings = UserSettings(
    userId: userId,
    randomPhotoOffset: randomPhotoOffset,
  );

  try {
    final request = ModelMutations.create(settings);
    final response = await Amplify.API.mutate(request: request).response;
    if (response.errors.isEmpty) {
      Log.i("User settings updated: ${response.data}");
    } else {
      Log.e("Errors updating user settings: ${response.errors}");
    }
  } catch (e) {
    Log.e("Exception updating user settings: $e");
  }
}

schema.graphql This is the model definition required by Amplify

type UserSettings @model {
  id: ID!
  userId: String!
  randomPhotoOffset: Boolean
}

Note: After I typed this model, I ran amplify push and amplify codegen models, which successfully generated `ModelProvider.dart' and 'UserSettings.dart'. I have not modified those in any way.

Attempt 1

I have tried using AI to solve this issue; however, its solutions are not viable

One example is updating my settings_service with this

Future<void> updateUserSettings({
  required String userId,
  required bool randomPhotoOffset,
}) async {
  final settings = UserSettings(
    userId: userId,
    randomPhotoOffset: randomPhotoOffset,
  );

  try {
    final request = ModelMutations.create(
      settings,
      modelProvider: ModelProvider.instance,
    );
    final response = await Amplify.API.mutate(request: request).response;
    if (response.errors.isEmpty) {
      print("User settings updated: ${response.data}");
    } else {
      print("Errors updating user settings: ${response.errors}");
    }
  } catch (e) {
    print("Exception updating user settings: $e");
  }
}

But ModelMutations.create does not have a modelProvider parameter available. I still think the issue lies in main.dart

Attempt 2

I have also tried changing configureAmplify() to this

  void _configureAmplify() async {
    try {
      final authPlugin = AmplifyAuthCognito();
      final apiPlugin = AmplifyAPI();

      Amplify.addPlugins([authPlugin, apiPlugin]);

      await Amplify.configure(amplifyconfig);
      setState(() {
        _amplifyConfigured = true;
      });
    } catch (e) {
      print("Amplify configuration failed: $e");
    }
  }
  

Even though no syntax errors arise, the error above still occurs

Overview

My goal is to make a Flutter ios app with AWS. I am facing an issue when adding a persistent settings model to users, who will each have a corresponding settings model from their chosen items, like in any normal app.

More specifically, I want to have a single settings entry called randomPhotoOffset, which is boolean. I was advised to use Amplify and DynamoDB to store user settings because it is scalable and offers more choices, compared to just using Cognito.

My workspace and versioning

1. Using Amplify Gen 1 and CLI
2. amplify_flutter: ^2.6.0
3. amplify_auth_cognito: ^2.5.0
4. amplify_api: ^2.6.0
5. amplify_datastore: ^2.6.0
6. Flutter sdk: ^3.5.4 I have updated my `pubspec.yaml' and my packages are all up to date and no versioning conflict occurs

Also testing on Simulator with device iPhone 16 Pro Mac on M4 Pro

The only issue

The only issue I am facing is an error I get when I toggle a button that changes one of my settings.

Exception updating user settings: ApiOperationException { "message": "No modelProvider found", "recoverySuggestion": "Pass in a modelProvider instance while instantiating APIPlugin" }

My code

main.dart This function is called after WidgetsFlutterBinding.ensureInitialized(); and before runApp().

Future<void> configureAmplify() async {
  try {
    final authPlugin = AmplifyAuthCognito();
    final apiPlugin = AmplifyAPI();
    final dataStorePlugin =
        AmplifyDataStore(modelProvider: ModelProvider.instance);

    Amplify.addPlugins(
      [authPlugin, dataStorePlugin, apiPlugin],
    );
    await Amplify.configure(amplifyConfig);

    // Start DataStore to register the model provider for GraphQL operations.
    await Amplify.DataStore.start();
  } on Exception catch (e) {
    Log.e("Error configuring Amplify: $e");
  }
}

settings.dart This is the only relevant function that is called once a button is pressed. Changes occur immediately after toggling, so a save button is avoided

Future<void> _toggleRandomPhotoOffset(bool newValue) async {
    setState(() {
      _randomPhotoOffset = newValue;
    });
    try {
      // Retrieve the current user's ID from Amplify Auth.
      final authUser = await Amplify.Auth.getCurrentUser();
      await updateUserSettings(
        userId: authUser.userId,
        randomPhotoOffset: newValue,
      );
    } catch (e) {
      Log.e("Error retrieving user or updating settings: $e");
    }
  }

settings_service.dart Here, updateUserSettings is defined

Future<void> updateUserSettings({
  required String userId,
  required bool randomPhotoOffset,
}) async {
  // Create a new UserSettings object.
  final settings = UserSettings(
    userId: userId,
    randomPhotoOffset: randomPhotoOffset,
  );

  try {
    final request = ModelMutations.create(settings);
    final response = await Amplify.API.mutate(request: request).response;
    if (response.errors.isEmpty) {
      Log.i("User settings updated: ${response.data}");
    } else {
      Log.e("Errors updating user settings: ${response.errors}");
    }
  } catch (e) {
    Log.e("Exception updating user settings: $e");
  }
}

schema.graphql This is the model definition required by Amplify

type UserSettings @model {
  id: ID!
  userId: String!
  randomPhotoOffset: Boolean
}

Note: After I typed this model, I ran amplify push and amplify codegen models, which successfully generated `ModelProvider.dart' and 'UserSettings.dart'. I have not modified those in any way.

Attempt 1

I have tried using AI to solve this issue; however, its solutions are not viable

One example is updating my settings_service with this

Future<void> updateUserSettings({
  required String userId,
  required bool randomPhotoOffset,
}) async {
  final settings = UserSettings(
    userId: userId,
    randomPhotoOffset: randomPhotoOffset,
  );

  try {
    final request = ModelMutations.create(
      settings,
      modelProvider: ModelProvider.instance,
    );
    final response = await Amplify.API.mutate(request: request).response;
    if (response.errors.isEmpty) {
      print("User settings updated: ${response.data}");
    } else {
      print("Errors updating user settings: ${response.errors}");
    }
  } catch (e) {
    print("Exception updating user settings: $e");
  }
}

But ModelMutations.create does not have a modelProvider parameter available. I still think the issue lies in main.dart

Attempt 2

I have also tried changing configureAmplify() to this

  void _configureAmplify() async {
    try {
      final authPlugin = AmplifyAuthCognito();
      final apiPlugin = AmplifyAPI();

      Amplify.addPlugins([authPlugin, apiPlugin]);

      await Amplify.configure(amplifyconfig);
      setState(() {
        _amplifyConfigured = true;
      });
    } catch (e) {
      print("Amplify configuration failed: $e");
    }
  }
  

Even though no syntax errors arise, the error above still occurs

• flutter
• amazon-web-services
• aws-amplify

Share Improve this question Follow edited Feb 13 at 20:15 VLAZ 29.1k99 gold badges6262 silver badges8484 bronze badges asked Feb 13 at 15:54 fadedpigeon_47fadedpigeon_47 51333 silver badges1111 bronze badges

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1 Answer 1

Sorted by: Reset to default 0

This issue was suprisingly fixed by changing the order in which plugins were added.

In main.dart

from

Amplify.addPlugins([authPlugin, dataStorePlugin, apiPlugin]);

To

Amplify.addPlugins([dataStorePlugin, authPlugin, apiPlugin]);

And the following commands were required for me

flutter clean

flutter pub get

flutter run -d iPhone

Don't know why this was never referenced or needed by Amplify as authPlugin has no requirements for dataStore

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